Control switch



April 9, 1935; M. E. HENNING CONTROL SWITCH Filed July 3, 1930 @ye/MW Patented Apr. 9, 1935 UNITI-:Dv STATES CONTROL SWITCH Malcolm E. Henning, Des Moines, Iowa, assigner to Penn Electric Switch Co., Des Moines, Iowa,

a corporation of Iowa Application July 3, 1930, Serial'No. 465,595

1 Claim. Anobject of my invention is tofprovde an automatic control switch having general utility and provided with primary and secondary control circuits, one of which has a'dela'yed action with respect tothe other one.

^ collect therein and cause an explosion upon the automatic control devices for the oil'burner again rendering it operative. f l

A further' object isto provide in connection ywith a solenoid opened oil supply valve controlled by a lprimary circuit control device, a Vsecondary circuit control device for the blower motor for causing it to continue to operate,l a predetermined lengthfof time, after the primary control ydevice has allowed the oil supply valve to close.

More particularly, it is my object to provide in connection with a solenoid opened oil supply valve, a blower motor switch consisting oi a switch arm operated by the solenoid armature and connected in the circuit of the blower motor, a thermostatic latch being provided for maintaining the switch arm in closed circuit -position during energization of the solenoid and simultaneous energization of a heating element vsurrounding the thermostatic latch bar whereby the switch arm may be retained by the thermostatic bar in lclosed circuit position, after the solenoid and heating element have been deenergized and until the heating element has cooled to such a point that it will unlatch the switch arm and allow it to move to open circuit position.

Still a further object is to provide magnetic means in connection with the switch arm for holding the switch contacts in engaged position and for assisting `in quick separation of the contacts when the switch arm moves to open circuit position.

Still a further object is to provide a contact on the switch arm movable with respect thereto so as to compensate for diiierent current voltages supplied to the solenoid, to compensate for vari'- ations in the dimensions of parts of the controll device, to compensate for an amount oi play required between the switch arm and the thermostatic latch and to assist in quick separation of Vthe switch contacts.

With these and other objects in view my invention consists in the construction, arrangement and (Cl. 20G-88) combination of the various parts of my device, whereby ythe objects contemplated are attained, ashereinafter more fully set forth, pointed out in my claim, and' illustrated iny the accompany ing drawing, in which: y

Figure 1 is a perspective view blower motor control device.

Figure 2 is avertical central sectionalview lci the same showing it in inoperative position.

Figure 3 is aside elevation 'of a'portion of the device'showing itin operative positonandv Figure 4 is a .diagrammatic vView rshowing a primary.. control device', my oil burner hlowe;` motor ycontrol device, and oil supply valve and a blower motor.

On the accompanying drawing, have used the reference'numeral lil to indicate a plate or other support usually included in the construction oi an oil burner for furnaces or thev like. Oil.-y burners of the kind for which my' control offiny` oil burner led device is designed include an oil valve il?, the

needle it of which is connected with an annature I6. The armature I6 is slidable within the core l8of a solenoid coil 2d and is adapted to l be raised whenever the coil is energized for opening the oil valve I2 and supplying oil to the oil burner.

A room thermostat 22 (see AFigure 4)v is usually connected in the. circuit of the solenoid coil 2d for energizing the same whenever the temperature oi a room to be heated by the oil` burner lowers to a predetermined degree and the room thermostat opens the circuit when the temperature rises to a predetermined degree.

A casing 25 surrounds the solenoid coil 2G and supports what I shall term a secondary control switch, considering the room thermostat 22 as a primary control switch.

The secondary control switch includes a switch arm 126 pivoted on a pin 2li. -A contact plate 3B has 'a nger extending into a socket 32 in the switch arm 2B and carries a contact 3G. Slight swinging movement of the plate Sii may be had relative to the switch arm 26 because of the nger extending into the socket 32.

A screw 36 extends through an opening in the contact plate 3@ for preventing side movement of the plate relative to the switch arm 26 and yet allowing up and down movement of the plate relative to the arm. A spring 38, interposed between the head of the screw 36 and the contact plate 30, normally retains the plate against the switch arm, as shown in Figure 2.

A stationary contact 40 is mounted on a stationary contact plate 42. The plate 42 is held in position on a boss 4e by means of a screw d5. The screw 46 also retains a permanent magnet 4t in position onthe boss 4t to act upon 'arman ture portions 5@ of the contact plate 32. The stationary contact plate 42 is suitably insulated from the boss ed, the screw lo and the magnet dit by insulation washers and sleeves, as shown in Figure 2.

An operative connection is provided between the armature it and the switch arm 26, as wih now be described A post 52 extends upwardly from the armature it through an enlarged open-L1 ingtl in the switch arm 2t. A leaf spring 5t is secured to the switch arm 26 and extends over the opening 541. The spring 56 is adapted to be engaged by the post 52 whenever the same moves upwardly, as shown, for instance, in Figure 3.

A weight 5t is provided for the switch arm 2t to normally retain it in open circuit position. 'Ihe weight 58 is pivoted to the switch arm 255 by means oi a pin Ed. The weight 5d has stop shoulders @2 and et adapted to engage a iiange 65 on the solenoid casing 24 to limit movement of the switch arm 26 in either direction.

A thermostatic latch bar E@ is provided for the switch arm 2t and is secured to the base l@ by a screw 68. An adjusting screw l@ is provided for adjusting the position of the latch 66 relative to the portion of the switch arm 26 with which it coacts and for consequently adjusting the tim ing of the operation of the thermostatic latch, as will hereinafter be more fully set forth. The heating element 12 is wrapped around the thermostatic latch bar 66.,

Practical operation Referring to Figure 4, the oil burner blower motor control is shown in inoperative position.

When the room thermostat 22 calls for heat, it-

will close the current supply throughthe solenoid coil 2u and the heating element i2 whereby the oil valve l2 will be opened due to the action of the solenoid 2u on the armature it. The post 52 will engage the spring E@ for closing the switch contacts 3d and du, as shown in Figure 3, the switch arm then being in the dotted line position shown in Figure 2. This will establish a circuit through the blower motor 'it so that both oil and air are supplied to the oil burner.

The eect of the heat from the heating ele ment 'i2 on the thermostatic bar 66 will flex the bar to they dotted line position shown in Figure 2.

When the room thermostat 22 moves to open circuit position, the oil valve i2 will immediately close, the switch arm 26 will drop down against the end of the thermostatic bar 66, but the contacts 3d and dll! will still remain in engagement with each other. This causes continued operation of the blower motor id to clear the combustion chamber of the furnace of any oil or explosive vapor which might be therein.

After a short period of time, the thermostatic latch bar 66 will flex to the solid line position shown in Figure 2 and allow the blower motor circuit to be broken.

'The contact plate Sii is mounted movable relae tive to the switch arm 26 so that when the arma ture i6 raises to the position shown in Figure 3, the contacts 3d and @u may rst engage and then the switch arm 26 may be moved further so as to space the arm above the upper end of the latch bar 66, as shown in dotted lines in Figure 2. Then when the solenoid 2u is subsequently deenergized, the switch arm 2G will drop to a position resting on the top of the latch bar 66, but the contacts 3d and #it will still remain in engagement with eachl other. Thus it is seen that the movability of the contact plate 3G relative to the switch arm 26 is important.

The leaf spring 56 provides a resilient operative connection between the plunger I6 and the switch arm 26 whereby to prevent vibration being imparted from the post 52 to the switch arm. This is especially desirable when alternating current is used.

Some changes may be made in the construction and arrangement of the parts of my device with out departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

In a control switch, a pivoted switch lever, electro responsive means for moving the same, a leaf spring element carried by and secured to said switch lever, said electro responsive means being engageable therewith when energized, whereby said lever is moved by tension of said leaf spring, a movable contact carried by said switch lever, a stationary contact for coaction therewith, one of said contacts being movable under tension with respect to its means of support, and a thermal latch for said switch lever in the position it assumes when said electro responsive means is energized.

MALCOLM E. HEN'NING. 

